Before writing a UIM, you should be familiar with z/OS HCD User's Guide, which explains:

• How to use the HCD facility Query supported hardware and installed UIMs
• How to use the batch utility “Print Supported Hardware Report”
• How to define control units, devices, and ESCON directors in HCD.

This chapter includes the following information:

• UIM data areas
• UIM environment
• UIM recovery
• Steps to write a UIM
• Installing a UIM
• UIM service routines
• UIM macros
• UIM data tables (UDTs)
• Testing UIMs

Sample of a Unit Information Module (UIM) and Sample of a Unit Data Table (UDT) shows you a sample of a UIM and UDT with detailed explanation. The samples are members of SYS1.SAMPLIB(CBDSUIM) and (CBDSUDT).